Construction advances on HNTB-designed Laguna Niguel-San Juan Capistrano Passing Siding Project

Track, roadway improvements and associated structures are progressing

SANTA ANA, Calif. (Nov. 19, 2020) – The construction phase for Orange County Transportation Authority’s Laguna Niguel-San Juan Capistrano Passing Siding project continues to be on track for an expected completion in 2021.

Designed by HNTB, the project adds 1.8 miles of new passing siding railroad track between the Laguna Niguel/Mission Viejo Metrolink Station and Trabuco Creek in San Juan Capistrano. The passing siding track runs adjacent to the existing track, allowing trains traveling in opposite directions to pass each other without stopping. When completed, it will reduce delays, increase safety, and provide more reliable rail service on the Los Angeles-San Diego San Louis Obispo rail corridor.

“We are pleased to see the ongoing construction progress being made by OCTA on the double track project that is bringing this essential project closer to completion,” said Graham Christie, PE, HNTB associate vice president and Southern California rail leader. “Our design and engineering team is proud to serve OCTA on this major Southern California infrastructure project that will result in increased safety and efficiency for rail passengers and the community.”

HNTB is the civil engineer on the project, which includes the design of a new passing siding and new trackwork, extended culverts, the replacement of a timber bridge with a concrete box culvert, and improvements at a grade crossing with associated roadwork. Work involves close coordination with the railroad signal designer for the removal of a signal control point and the installation of two new control points throughout the 1.8 mile passing siding.

Throughout the design phase, the firm developed innovative solutions to reduce construction costs, avoid significant utility relocations, and minimize impacts to railroad operations. Other improvements included relocating a spur track; improving the private crossing from Camino Capistrano to Saddleback Church Rancho Capistrano; and reprofiling approximately 600 feet of Camino Capistrano to improve roadway safety.

In Southern California, HNTB is involved in numerous high-profile rail projects, including the Metrolink Burbank Airport North train station; OCTA’s Anaheim Canyon Station project; Los Angeles County Metropolitan Transportation Authority’s Brighton to Roxford Double Track Project in east San Fernando Valley; LOSSAN corridor double-track projects for the San Diego Association of Governments, including Batiquitos Lagoon; North Oceanside; San Dieguito Double Track and Special Events Platform; and North County Transit District’s Positive Train Control safety system. The projects encompass planning, environmental, drainage, track design, civil engineering, and positive train control integration.


The Metrolink train is on the original mainline track and the new passing siding is the track adjacent with the new concrete ties.

Pictured is the at-grade crossing at Rancho Capistrano, which is designated as a private crossing and provides the only access across the railroad tracks to Saddleback complex (church and soccer fields).